Recently, degradable materials such as poly lactic acid (PLA) were used as Guided Tissue Regeneration (GTR) membranes and/or Guided bone Regeneration(GBR) membranes in dentistry. However, these membranes did not have any biological function such as the facilitation of cell adhesion. Additionally, they do not have a 3-dimensional porous structure to arrange the cell into the part of the organization loss. In this study, PLA 3-dimensional porous scaffold was fabricated by combination of porogen method and freeze-dry method. PLA porous scaffold surface was hydrolyzed with alkaline solution and collagen which was cell-adhesive protein was immobilized on PLA porous scaffold surface using water-soluble carbodiimide. The initial attachment of human gingival fibroblasts was examined. PLA porous scaffold with collagen immobilized after 1 hr alkaline hydrolysis showed significantly higher amount of initial cell attachment than PLA porous scaffold without collagen immobilization.
The purpose of this study is to clarify the possibility of continuous measurement on cell proliferation and calcification using a scintillator-incorporated culture plate (Cytostar-T). Mouse osteoblast-like cells (MC3T3-E1) were cultured using culture plates (Cytostar-T) with culture media including two nuclides (3H-thymidine and 45CaCl2), followed by continuous measurements of 3H and 45Ca were performed in the same well for 21 days using a micro-plate scintillation counter. The results showed it was possible to measure both cell number and the amount of calcification simultaneously and continuously. These results indicate that measurement using a scintillator- incorporated culture plate is promising method with improving the efficiency of the cells, the reagents and the materials used in vitro tests.
Surgeons hope to avert disfigured scar formation of incision line after surgery from the aspect of esthetics. Flap designs in periapical surgery were clinically evaluated in relation to postoperative disfigured scar formation. Fifty nine systemically healthy patients who need endodontic periapical surgery were operated by means of two types of flap designs, i.e., semilunar and Luebke-Ochsenbein, followed by the continuous locking suture technique using Oval-M® (6-0, polypropylene). Postoperative scarring at two weeks or one month was observed. The Luebke-Ochsenbein flap design showed less scar formation than semilunar flap during experiment period showing particularly unnoticeable scar formation at one month postoperatively. The results indicated the Luebke-Ochsenbein method was recommended ideal flap design without disfigured postoperative scar formation followed by continuous locking suture technique using Oval-M®.
Objectives: The white Mineral Trioxide Aggregate / ProROOT MTA® is authorized in Japan from October, 2006, and it is sold. There is necessity evaluating ProROOT MTA®. For reports of the inflammatory reaction of the pulp tissue which the possibility that some problem of ultra-microelement, arsenic trioxide and the strong alkali pH included in MTA inhibit mineralized contribution. Materials and method: We got patient compliance and used 4 cases caries-free human permanent third molars and pre-molars scheduled for extraction for orthodontic reasons from 19 and 22 years old woman, in which mechanical pulp exposures, hemostasis in 2%NaClO, dried with disinfection pledget and capped with ProROOT MTA®. We reviewed human pulp tissue regeneration of 2 weeks and 4 weeks by H-E staining for histological regeneration and S100 positive staining for dental pulp neurotization. Results and discussion: The histological transendothelial time comparison is not possible so that a condition varies with human. As for the results, the regenerated odontoblast and the regeneration of the dental pulp nervous system are not seen in pulp tissue under ProROOT MTA® which did pulp capping almost in 2 weeks statue. However, the hyperaemia and the tissue degeneration were not recognized around ProROOT MTA® particle. We showed the osteoid or cement-like dentin-bridge formed by about 200 µm width in 4 weeks statue. Normal pulp tissue and odontoblast are recovering the boundary surface right under the mineralized layer. The Schwann cells were not observed in the statue at all for 2 weeks statue, but there was much statue which regenerated right under mineralization lamina, and the Schwann cells were observed in statue for 4 weeks statue. Hyperaemia and tissue degeneration were not found in human pulp tissue around the MTA particle which did extravasation for 2 and 4 weeks statue of both specimens. We think ultramicro arsenic trioxide and alkali pH does not have the influence with the human pulp tissue and biological regulation is considered to be it. Also, there seemed to be association in dental pulp neurotization and dentin mineralization from these specimens.
We examined the histology and age-related compositional changes of subgingival calculus in male and female. The calculus samples of male and female aged 10 to 60 were whitish. Samples from those in the 70's were yellowish. In polished samples from females, three lamella structures were clear and chromatic difference was present in lamina of inner layers, middle layers, and outer layers. In samples from both males and females, ages 10 to 20, scanning electron microscopy revealed spherical crystal structure of the calculus; in samples from 30 to 70-year olds, crystal structure was irregular. Granule diameters were found to be smallest in teenagers, largest in 40 to 49-year olds, and then gradually shrinking throughout aging. EPMA analysis revealed calculus composition to be, in decreasing amounts, Ca, P, Na and Mg. Samples from 70-year olds showed a higher Ca/P ratio than those from 10, 20 and 40-year olds. In the line analysis of EPMA, there was more Mg content in the dark band than in the light band. HA was detected by X-ray diffraction method in 10, 20, 40 and 70-year old samples, and OCP, W were detected in females' samples of 10, 20 and 40-year olds.
Dentin regeneration to the lost dentin is the supreme therapy to keep functionality, aesthetics and so forth in operative dentistry. In 2006, we demonstrated the human bone marrow mesenchymal stem cells (hMSCs) differentiated into odontoblast by the stimulation of Emdogain Gel and TNF-α set. In 2008, we tried to demonstrate odontoblast that differentiated from hMSCs generate dentin under the artificially synthesized appropriate scaffold and molecular signal in vitro. As a result, the differentiated cell tissue tested positive for osteocalcin by fluorescence antibody method and enzyme antibody technique and positive for calcium compounds with the alizarin red S staining. In addition, we detected the dentin-like tissue outside the cell walls by phase contrast microscopy. These results suggested that hMSCs differentiate into odontoblast and generate dentin using Emdogain Gel and TNF-α set and peptide hydrogel.
The mineralization accelerating adhesion materials that added EVA+C (RMSB) were produced experimentally, and we studied it about a bond strength and the biocompatibility. As a result, bond strength decreased with increase of the EVA+C addition ratio. But the level of the decrease was inhibited when SBP30 was treated. The RMSB group showed a tendency to growth similar to Control at the early phase, and cell count was higher than an SB (Superbond) at high ratio of EVA+C group. It was a combination of SBP30 and 7P (SB/EVA+C = 40wt%/60wt%) that showed a high bond strength and a good cell proliferation. Also, as a result of animal experiment, 7P had weaker inflammation than an SB and mineralized tissue formation was good. It was suggested that it was obtained high adhesive property and biocompatibility by adding EVA+C in an SB at the appropriate ratio in conclusion.